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import Vue from 'vue';

const isServer = Vue.prototype.$isServer;
const SPECIAL_CHARS_REGEXP = /([\:\-\_]+(.))/g; // eslint-disable-line no-useless-escape
const MOZ_HACK_REGEXP = /^moz([A-Z])/;
const ieVersion = isServer ? 0 : Number(document.documentMode);

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const trim = function(string) {
    return (string || '').replace(/^[\s\uFEFF]+|[\s\uFEFF]+$/g, '');
};
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const camelCase = function(name) {
    return name
        .replace(SPECIAL_CHARS_REGEXP, function(_, separator, letter, offset) {
            return offset ? letter.toUpperCase() : letter;
        })
        .replace(MOZ_HACK_REGEXP, 'Moz$1');
};

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export const on = (function() {
    if (!isServer && document.addEventListener) {
        return function(element, event, handler) {
            if (element && event && handler) {
                element.addEventListener(event, handler, false);
            }
        };
    } else {
        return function(element, event, handler) {
            if (element && event && handler) {
                element.attachEvent('on' + event, handler);
            }
        };
    }
})();

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export const off = (function() {
    if (!isServer && document.removeEventListener) {
        return function(element, event, handler) {
            if (element && event) {
                element.removeEventListener(event, handler, false);
            }
        };
    } else {
        return function(element, event, handler) {
            if (element && event) {
                element.detachEvent('on' + event, handler);
            }
        };
    }
})();

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export const once = function(el, event, fn) {
    var listener = function() {
        if (fn) {
            fn.apply(this, arguments);
        }
        off(el, event, listener);
    };
    on(el, event, listener);
};

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export function hasClass(el, cls) {
    if (!el || !cls) return false;
    if (cls.indexOf(' ') !== -1) throw new Error('className should not contain space.');
    if (el.classList) {
        return el.classList.contains(cls);
    } else {
        return (' ' + el.className + ' ').indexOf(' ' + cls + ' ') > -1;
    }
}

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export function addClass(el, cls) {
    if (!el) return;
    var curClass = el.className;
    var classes = (cls || '').split(' ');

    for (var i = 0, j = classes.length; i < j; i++) {
        var clsName = classes[i];
        if (!clsName) continue;

        if (el.classList) {
            el.classList.add(clsName);
        } else if (!hasClass(el, clsName)) {
            curClass += ' ' + clsName;
        }
    }
    if (!el.classList) {
        el.className = curClass;
    }
}

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export function removeClass(el, cls) {
    if (!el || !cls) return;
    var classes = cls.split(' ');
    var curClass = ' ' + el.className + ' ';

    for (var i = 0, j = classes.length; i < j; i++) {
        var clsName = classes[i];
        if (!clsName) continue;

        if (el.classList) {
            el.classList.remove(clsName);
        } else if (hasClass(el, clsName)) {
            curClass = curClass.replace(' ' + clsName + ' ', ' ');
        }
    }
    if (!el.classList) {
        el.className = trim(curClass);
    }
}

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export const getStyle =
    ieVersion < 9
        ? function(element, styleName) {
              if (isServer) return;
              if (!element || !styleName) return null;
              styleName = camelCase(styleName);
              if (styleName === 'float') {
                  styleName = 'styleFloat';
              }
              try {
                  switch (styleName) {
                      case 'opacity':
                          try {
                              return element.filters.item('alpha').opacity / 100;
                          } catch (e) {
                              return 1.0;
                          }
                      default:
                          return element.style[styleName] || element.currentStyle
                              ? element.currentStyle[styleName]
                              : null;
                  }
              } catch (e) {
                  return element.style[styleName];
              }
          }
        : function(element, styleName) {
              if (isServer) return;
              if (!element || !styleName) return null;
              styleName = camelCase(styleName);
              if (styleName === 'float') {
                  styleName = 'cssFloat';
              }
              try {
                  var computed = document.defaultView.getComputedStyle(element, '');
                  return element.style[styleName] || computed ? computed[styleName] : null;
              } catch (e) {
                  return element.style[styleName];
              }
          };

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export function setStyle(element, styleName, value) {
    if (!element || !styleName) return;

    if (typeof styleName === 'object') {
        for (var prop in styleName) {
            if (styleName.hasOwnProperty(prop)) {
                setStyle(element, prop, styleName[prop]);
            }
        }
    } else {
        styleName = camelCase(styleName);
        if (styleName === 'opacity' && ieVersion < 9) {
            element.style.filter = isNaN(value) ? '' : 'alpha(opacity=' + value * 100 + ')';
        } else {
            element.style[styleName] = value;
        }
    }
}

export function createPopupWrap() {
    const page = document.getElementById('__nuxt');
    const childNodes = page.childNodes;
    let popup;
    for (let i = 0, l = childNodes.length; i < l; i++) {
        const item = childNodes[i];
        if (item.nodeType !== 1) continue;
        if (/\bpopup-wrap\b/.test(item.className)) {
            popup = item;
            break;
        }
    }
    if (!popup) {
        popup = document.createElement('div');
        popup.classList.add('popup-wrap');
        page.appendChild(popup);
    }
    return popup;
}

export function createMountNode(page) {
    page = page || this.App;
    const node = document.createElement('div');
    const popup = this.createPopupWrap(page);
    popup.appendChild(node);
    return node;
}
